The invention relates to a device for preparing substances, dissolved in solvent, for mass-spectrometric or similar analysis thereof, it being possible, after removal (evaporation) of the solvent, for the substance to be introduced by a sample holder of small dimensions into the mass spectrometer (ionisation chamber) or the like, preferably for the mass-spectrometric off-line analysis of fractions spearated in a liquid chromatograph (LC).
It is known and customary practice to combine liquid chromatographs (LC) and mass spectrometers (MS) for a great number of analytical examinations. The fractions, which are separated in the liquid chromatographs, of the substances to be analysed emerge from the LC column in solvents and are collected in vessels. The solvent must be evaporated for the subsequent (mass-spectrometric) analysis. Then, in a further operation the substance (sample) left as a residue is passed into a relatively small crucible (sampel holder) which can be introduced into the ion source of the mass spectrometer. In place of the crucible, a wire or differently designed sample holder can be used to introduce the substance into the mass spectrometer.
To transfer the substance from the collecting vessel of the LC into or onto the sample holder of the mass spectrometer, it is often necessary for the fraction concerned to be dissolved once more in a solvent and for the latter to be subsequently evaporated. This multi-stage dissolving and evaporating process is necessary due to, on the one hand, the relatively large capacity of the collecting vessel (at least 1 cm.sup.3) and, on the other hand, the, in contrast, small dimensions of the sample holder. The fraction emerging from the LC is normally yielded in a strongly diluted form so that the collecting vessel must be correspondingly dimensioned for this purpose.